Psycholinguistics: Crash Course Linguistics #11

Summary

This Crash Course Linguistics episode explores the intricate relationship between language and the brain. It delves into the 19th-century discoveries of Broca's and Wernicke's areas, which are linked to speech production and comprehension. The episode also touches on aphasia, the effects of brain injuries on language, and the concept of neuroplasticity. It highlights various psycholinguistic experiments, including the 'kiki/bouba' test, which demonstrates the connection between language and sensory experiences, and the use of tools like EEG and fMRI to study the brain's language processing. The video concludes by emphasizing the complexity of language acquisition and the ongoing quest to understand the brain's role in linguistics.

Takeaways

• 🧠 The human brain is the organ responsible for our linguistic abilities, including phonology, semantics, syntax, and reading.
• 🔍 Psycholinguistics is the study of the interaction between language and the brain, aiming to understand how language is produced and interpreted.
• 📚 Interest in the brain-language relationship increased in the 19th century with the study of language disorders and post-mortem brain examinations.
• 🧐 Aphasia is a condition where language abilities are affected due to brain injury, leading to the discovery of Broca's and Wernicke's areas.
• 🗣️ Broca's area, associated with speech production, is typically located in the left frontal lobe of the brain.
• 🤔 Wernicke's area, linked to language comprehension, is usually found in the left temporal lobe.
• 🧬 Neuroplasticity refers to the brain's ability to reorganize itself by forming new neural connections throughout life, which can be observed in language recovery post-injury.
• 👂 Language areas are predominantly in the left hemisphere but can vary, especially in left-handed or ambidextrous individuals.
• 🤓 Psycholinguistic experiments, such as the Tip of the Tongue phenomenon, reveal how our minds organize language and partial information retention.
• 🎨 The kiki/bouba experiment demonstrates a cross-sensory relationship between words and shapes, indicating some non-arbitrary aspects of language.
• 📊 Various techniques like priming, gating, and eyetracking are used by psycholinguists to study language processing in the brain.
• 🧩 Tools like EEG and fMRI provide insights into the timing and location of brain activity during language processing, each with its strengths and limitations.

Q & A

What is the main focus of Crash Course Linguistics?

The main focus of Crash Course Linguistics is to explore the relationship between language and the brain, including how language is produced, interpreted, and the role of the brain in linguistic abilities.

What is the role of the brain in language acquisition?

The brain is responsible for acquiring complex linguistic skills such as phonology, semantics, syntax, and reading. It helps in writing, composing texts, and interpreting non-verbal cues like facial expressions or emojis.

What is psycholinguistics?

Psycholinguistics is the field that studies the structure of language and the cognitive processes involved in the use of language. It helps in understanding where and how language happens in the brain.

How did 19th-century researchers establish the link between brain injuries and language disorders?

19th-century researchers observed people with language disorders, then examined their brains post-mortem. They correlated damage to specific brain areas with changes in language abilities, leading to the discovery of aphasia types like Broca's and Wernicke's.

What are Broca's aphasia and Wernicke's aphasia?

Broca's aphasia is characterized by an ability to understand language but difficulty in speaking fluently and using grammar, while Wernicke's aphasia involves fluent but nonsensical speech, indicating issues with the meaning of language.

What is meant by neuroplasticity in the context of language and the brain?

Neuroplasticity refers to the brain's ability to adapt by building and reorganizing neural connections in response to learning or injury, which can affect language abilities and recovery from language disorders.

Why is the study of language production errors important for psycholinguists?

Language production errors, such as spoonerisms or tip of the tongue experiences, provide insights into the cognitive processes involved in language use and how the mind organizes linguistic information.

What is the 'Tip of the Tongue' experience and what does it reveal about language processing?

The 'Tip of the Tongue' experience is when a person knows they know a word but cannot recall it. It reveals that our brains can retain partial information about a word, such as its first letter or meaning, even when the complete word is inaccessible.

How does the 'kiki/bouba' experiment relate to the idea that language is tied to sensory experiences?

The 'kiki/bouba' experiment demonstrates that people tend to associate certain sounds with specific shapes based on sensory perceptions, suggesting that language is not entirely arbitrary and is connected to other sensory experiences.

What are some of the techniques used by psycholinguists to study language processing in the brain?

Techniques used by psycholinguists include priming experiments, gating experiments, eyetracking studies, and the use of equipment like EEG and fMRI to measure electrical activity and blood oxygen levels in the brain during language tasks.

How do garden path sentences illustrate the way we process language?

Garden path sentences are sentences that initially seem to follow one grammatical structure but then require re-evaluation. They illustrate that we process language in real-time, constantly updating our understanding as we receive new information.

What are the limitations of using EEG and fMRI in psycholinguistic studies?

EEG is precise about the timing of brain activity but imprecise about its location, and can be affected by external factors like blinking. fMRI is precise about the location of activity but less precise about the timing, and is expensive and uncomfortable for participants.

What does the script suggest about the need for caution when interpreting results from psycholinguistic studies?

The script suggests that caution is needed because there is individual variation in brain organization, and much of the psycholinguistic work has been conducted with small samples of people who speak dominant languages, which may not be representative of all language users.

Outlines

00:00

🧠 The Brain and Language: Psycholinguistics

This paragraph introduces the field of psycholinguistics, which explores the relationship between language and the brain. It explains that the brain is crucial for language acquisition and comprehension, including complex linguistic skills. The script discusses the historical interest in this relationship, starting from the 19th century with the study of aphasia and the discovery of Broca's and Wernicke's areas. It also touches on the complexities of the brain's role in language, including the phenomenon of neuroplasticity and the variability of language areas in the brain, especially among left-handed or ambidextrous individuals. The paragraph concludes with the importance of understanding language errors as they reveal insights into the cognitive processes involved in language.

05:04

🔍 Psycholinguistic Experiments and Language Perception

This paragraph delves into various psycholinguistic experiments that help understand how language is processed in the brain. It discusses the kiki/bouba experiment, which demonstrates a cross-linguistic tendency for certain sounds to be associated with specific shapes, suggesting a link between language and sensory experiences. The paragraph also covers priming experiments, gating experiments, and the study of swearing's effect on pain tolerance. It then describes the use of eyetracking and EEG to analyze sentence processing and neural activity, respectively. The use of fMRI for precise localization of brain activity during language tasks is also mentioned, along with the trade-offs between EEG and fMRI in terms of temporal and spatial precision.

10:04

📚 Reflections on Psycholinguistic Research and Future Directions

The final paragraph reflects on the progress and limitations of psycholinguistic research. It acknowledges the individual variation in brain organization and the need for caution when interpreting data from advanced brain-imaging machines. The script points out the predominance of research on speakers of dominant languages and the need for more inclusive studies. It concludes by emphasizing the ongoing nature of the field, with much still to be learned about how we learn language and the intricate connection between the brain and linguistic abilities.

Keywords

💡Linguistics

Linguistics is the scientific study of language and its structure. It encompasses the analysis of various aspects of language, including phonetics, phonology, syntax, semantics, and pragmatics. In the context of the video, linguistics is the overarching theme, as it discusses how the brain processes and produces language, highlighting the importance of understanding the brain's role in linguistic abilities.

💡Brain

The brain is the central organ of the nervous system, responsible for cognitive functions and behaviors. The video emphasizes the brain's role in language acquisition and use, including the development of phonology, semantics, syntax, and reading skills. It also discusses how damage to specific areas of the brain can lead to language disorders known as aphasia.

💡Psycholinguistics

Psycholinguistics is the field that explores the relationship between language and the mind, particularly how language is processed, produced, and understood by the brain. The video introduces psycholinguistics as a way to understand where and how language occurs in the brain, using various methods to study this relationship.

💡Aphasia

Aphasia is a language disorder that results from damage to the brain, affecting a person's ability to communicate effectively. The video mentions aphasia as a condition that helps researchers understand the brain's role in language by observing the correlation between brain injuries and changes in language abilities.

💡Broca's Aphasia

Broca's aphasia is a type of aphasia characterized by difficulty in speech production while comprehension remains relatively intact. Named after Paul Broca, the video explains that damage to Broca's area, located in the left frontal lobe of the brain, affects a person's ability to speak fluently and use grammar correctly.

💡Wernicke's Aphasia

Wernicke's aphasia is another type of language disorder where individuals speak fluently but produce nonsensical sentences due to impaired comprehension. The video describes Wernicke's area, near the left ear, as the part of the brain associated with understanding the meaning of language.

💡Neuroplasticity

Neuroplasticity refers to the brain's ability to adapt and reorganize itself by forming new neural connections throughout life. The video discusses how recent research has shown that the brain can compensate for damage to language areas, demonstrating the brain's capacity for change and adaptation.

💡Tip of the Tongue

The 'Tip of the Tongue' experience is a phenomenon where a person knows a word but cannot recall it at the moment. The video uses this concept to illustrate how our brains can retain partial information about a word, such as its meaning or first letter, even when the complete word is not accessible.

💡Morphosyntax

Morphosyntax refers to the grammatical structure of language, including the arrangement of words and the use of morphemes (the smallest meaningful units of language). The video explains that Broca's area affects a person's ability to use morphosyntax, impacting the fluency and grammaticality of speech.

💡Priming

In psycholinguistic experiments, 'priming' is a technique where one word or concept is presented to a participant to influence their response to subsequent words or concepts. The video describes how priming can be used to test the relatedness of words in the brain and measure the speed of cognitive responses.

💡Gating Experiments

Gating experiments are a method used in psycholinguistics to determine how much of a word a participant needs to hear or see to understand its meaning. The video uses this concept to explain that sounds in language are not always produced in discrete sequences and that listeners use partial information to interpret words.

💡EEG

EEG, or electroencephalography, is a neuroimaging technique that measures electrical activity in the brain. The video mentions EEG as a tool used by psycholinguists to study the brain's reaction to semantically unexpected information, such as the word 'socks' in the sentence about ice cream.

💡fMRI

fMRI, or functional magnetic resonance imaging, is another neuroimaging technique that measures changes in blood flow to map brain activity. The video explains that fMRI is precise in locating where brain activity occurs but less precise in determining the exact timing of these activities.

Highlights

The brain's role in language acquisition, including phonology, semantics, syntax, and reading.

Psycholinguistics as the field studying how language is produced and interpreted in the brain.

Historical 19th-century research linking brain injuries to language disorders, known as aphasia.

Identification of Broca's and Wernicke's areas and their respective roles in language production and comprehension.

The discovery of neuroplasticity, the brain's ability to adapt and reorganize after injury or learning.

Variability in brain organization, especially in left-handed or ambidextrous individuals.

Language errors as a window into the cognitive processes of language, such as spoonerisms and tip of the tongue experiences.

The Tip of the Tongue phenomenon and its implications for how our minds organize language.

Psycholinguistic experiments, like inducing Tip of the Tongue experiences to study cognitive processes.

The kiki/bouba experiment demonstrating the relationship between language and sensory experiences.

Marketers' use of sound symbolism in branding based on language tendencies.

Language-specific differences in the perception of the kiki/bouba test due to sound systems.

Priming experiments in psycholinguistics to measure the relatedness of words in the brain.

Gating experiments revealing the continuous process of language comprehension.

The use of eyetracking to study sentence processing and the resolution of garden path sentences.

EEG as a tool for measuring the timing of brain responses to semantic violations.

fMRI as a precise method for locating brain activity during language tasks.

The tradeoff between EEG's precision in time and fMRI's precision in spatial localization.

The need for caution in interpreting modern brain-imaging data due to individual variation and language dominance.

Transcripts

Hi, I'm Taylor and welcome to Crash Course Linguistics!

Language happens thanks to the brain.

This spongy thing sitting in our skull is responsible for our abilities to acquire complex linguistic skills like phonology, semantics, syntax and reading.

It’s what helps us write poems and compose texts, or get the meaning of a raised eyebrow or a string of random emojis.

Understanding the brain helps us understand how language is produced and interpreted.

We can point directly to the parts of our mouths and hands that are used to make language, but you can’t reach in and feel your own brain.

Luckily, over the years, people have devised a whole range of ways of looking at the brain to figure out where and how language happens.

This is the field of psycholinguistics.

[THEME MUSIC]

Interest in the relationship between language and the brain really picked up in the 19th century.

Researchers observed people with language disorders and then looked at their brains after they died.

If damage to one part of the brain from a stroke, dementia, or a head injury correlated with a difference in the subject’s ability to understand or produce language,

the scientists could predict there was a relationship there.

These kinds of injuries that affect our language abilities are known as aphasia.

Two famous kinds of aphasia discovered at the time are called Broca's aphasia and Wernicke's aphasia.

The areas of the brain related to each kind of aphasia therefore became known as Broca’s area and Wernicke’s area.

You may have heard about them in a Psychology or Anatomy class.

Broca's area is located around your left temple, and it was named after Paul Broca,

a 19th century French physician who noticed that people who'd been injured in this part of their brain acted in similar ways.

While they could still understand language, they could only produce maybe a handful of words, one at a time.

Broca’s area affected their ability to speak or sign in a fluid, grammatical way.

In other words, it affected their ability to use morphosyntax.

Right around the same time Broca was making his discovery, German physician Carl Wernicke discovered that if a different part of the brain was injured, there was a totally different effect.

The people injured in this spot, located just above your left ear, tended to talk in a way that sounded fluent and grammatical but was nonsensical.

Wernicke’s area is associated with the meaning of language.

But those 19th century studies were limited, and the brain is amazingly complex and flexible.

More recent research has found that some people can majorly damage Broca’s area and never develop aphasia.

Other people can re-learn how to speak through extensive practice building on their ability to sing, which is controlled by a different part of the brain.

These newer studies help us understand neuroplasticity,

the ability of the brain to flexibly build and connect parts of the brain in response to injury or as part of learning.

And though the language areas are usually located on the left hemisphere of the brain,

some people’s language areas are found predominantly in the right hemisphere, or spread across both sides

especially for left-handed or ambidextrous people.

So the relationship between language and the brain is even more complicated than we first thought.

Even now, errors and differences in language use can teach us about the different skills involved in language and how they're organized inside our minds.

We all sometimes forget a word that we know perfectly well, or accidentally swap words, parts of words, or idioms

what you might encounter as spoonerisms, tip of the tongue experiences or mixed metaphors.

These production errors tell us valuable things about how the mind handles language.

Like, you know when you just can't quite remember a word?

You know it, you almost have it, it's right there... you just can't retrieve it.

This phenomenon is known as a Tip of the Tongue experience,

and psycholinguists have found that people with a word on the tips of their tongues can often recall other information about it.

They might remember its meaning, its first letter, and sometimes how many syllables it has, but they can't quite recall the complete word.

Signed languages also have this phenomenon, which is known as Tip of the Fingers, naturally.

And signers experiencing Tips of the Fingers can also recall certain information about the sign they're seeking, especially the initial handshape and location of the hand.

They just can't recall the movement they'd need to complete the sign.

Tip of the Tongue and Finger experiences can show us how our thoughts are organized,

because we can have access to the first letter or initial hand position without having access to the remaining sounds or movement.

Knowing a word isn't a binary state of "yes" or "no" like a computer.

Our brains can also retain partial information.

Production errors are so useful that psycholinguists have techniques for trying to get people to make even more of them, so they can study those errors in a laboratory setting.

Psycholinguists can induce Tip of the Tongue or Finger experiences by asking people to translate words or to recall proper nouns.

Let’s head to the Thought Bubble to try another psycholinguistic experiment right here!

In a moment two shapes are going to appear on the screen.

Let’s decide which one is called kiki, and which one is called bouba.

Are you ready?

It’s more than likely that you called the shape on the left ‘bouba’ and the shape on the right ‘kiki’.

About nine out of every ten people make that choice.

Experiments have repeatedly shown that we think of voiceless stops like /k/ and high vowels like /i/ as small, sharp, crunchy, bright and spikey,

compared to voiced sounds like /b/ and rounded vowels like /u/, which are big, lumpy, dark and heavy, across many different languages.

The kiki/bouba experiment shows us that language is related to other sensory experiences.

Yes, words are still made up of arbitrary smaller parts, but it’s not completely 100% arbitrary, and this mapping between senses can show up in some general tendencies for naming things across language.

One large study showed that words for "nose" were more likely to have a nasal sound like /m/ or /n/, across many different languages.

Marketers are very aware of these links

bouba wouldn’t make a good name for a brand of crackers, but kiki would, because we generally want our crackers to be crispy.

But I’m sure bouba brand ice cream would taste much better — round and smooth and creamy.

Despite these general tendencies, there are also language-specific differences.

If your language doesn’t have a /b/ or /u/ sound, you might not think of ‘bouba’ as a possible word, so you might not associate it consistently with the blobby shape.

Different languages can also label the shapes differently depending on how their sound systems work.

Tone can influence how Mandarin speakers label these shapes.

The human brain doesn’t completely separate our linguistic knowledge from other knowledge of the world, and experiments like the kiki/bouba test help show that.

Thanks, Thought Bubble!

Or should I say...thought bouba?

That’s one kind of psycholinguistic experiment, but it’s far from the only one.

Psycholinguists might use a priming experiment to test how closely words are related in the brain.

They “prime” the participant with one word and measure the speed of their responses to other words.

Say a subject is primed with the word “dog” and then has a faster response to “cat” than to other words, we might conclude “cat” and “dog” are more closely related in the brain.

We can also use gating experiments, where we measure how much of a word a participant needs to hear or see until they know I’m saying, say, “park”, instead of “part”.

Gating experiments show that sounds aren't always produced in discrete sequences like our alphabet makes them look.

Like, most English speakers will produce the /k/ sound in "cube" a little bit differently than /k/ sound in "calm".

Psycholinguists have even looked into such mysteries as whether swearing helps us manage pain.

In that study, psycholinguists compared how long people could hold their hand in a bucket of ice water when they were allowed to swear and when they were not.

When people were allowed to swear, they could hold their hand in the iced water for longer.

Huh! I’m definitely going to find a practical application for this!

Other ways of figuring out what's going on in the brain when we use language involve using various kinds of equipment.

Eyetracking studies try to figure out what we're thinking about based on what we're looking at.

Let's say we're reading a sentence like this one:

Now, "The rabbit crouched on the cushion" is a totally reasonable English sentence,

so that's where most people assume it's going at first.

But then when we get to the word "seemed", we need to re-evaluate.

That's where eyetracking shows that a lot of people look back at the earlier portion of the sentence to figure out what's going on--in this case, a structure more like

"The rabbit that was crouched on the cushion seemed friendly."

Misleading sentences like these are called garden path sentences,

because they seem to "lead you up a garden path" of one interpretation before you realize that there's actually a different structure going on.

Eyetracking and garden path sentences show us that we process sentences as we're experiencing them

we don't wait until we've seen or heard a whole sentence before starting to figure out what's going on.

Electro-encephalography or EEG records the electrical activity of neurons firing through a cap of small sensors on the scalp.

A psycholinguist might hook a person up to an EEG and say a sentence like, “my favourite ice cream is chocolate and socks.”

“Socks” is semantically unexpected information in a sentence that we assumed would be about food, so the brain reacts accordingly.

And an EEG is especially good at indicating when a surge in electricity happens.

So here it might map a kind of surge, known as N400, around 400 milliseconds after hearing “socks.”

EEGs are quiet and relatively affordable, but they can be disturbed even by small things like blinking.

Plus, they’re not that great at mapping where things happen in the brain.

Functional magnetic resonance imaging, or fMRI, on the other hand, is relatively precise in locating brain activity

getting within a few millimeters of where the activity is happening.

It does this by measuring when there is increased oxygen in parts of the brain.

The more neural activity, or thinking, the more blood goes to the area of the brain, and that blood brings lots of oxygen to help those busy neurons.

For example, a psycholinguist might have someone learn, and recite back, a few words in a made-up language to see what happens in the brain when we try to learn a new language.

While fMRI is relatively precise in locating brain activity, it’s less precise at when that activity is happening.

It only gets within a few seconds, while thoughts can happen in fractions of a second.

They’re also very expensive and pretty dang uncomfortable to hang out in.

So there's sort of a tradeoff:

EEG machines are precise about time, but imprecise about space, whereas MRI machines are precise about space, but imprecise about time.

These machines, with their precise data and complex graphs, might seem like just the thing 19th century researchers like Broca and Wernicke needed to understand the link between the brain and language.

But really, we need to approach them with just as much caution as those older experiments.

There's still a lot of individual variation in how our brains get organized as we learn things,

and lots of psycholinguistics work has been done with small numbers of people who speak dominant languages like English.

So we only know a little about if and how being fluent in other languages affects what happens in the brain.

There’s always more to learn.

See you next time, when we talk about how we learn language in the first place!

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